Announcements pane of the Verbosity category

Use the Announcements pane of the Verbosity category in VoiceOver Utility to specify when you want VoiceOver to announce certain events, such as when a modifier key is pressed, and when to speak certain text, such as labels in dialogs.

To open VoiceOver Utility, press Command-F5 to turn VoiceOver on, then press VO-F8.